virtual ip's for Pg host

Hi All
we would like to implement a virtual  ip for two of our  of our PG db
hosts to help us with switching hosts with less downtime for clients, is
there  any specific change need to be done  on PG database hosts
configuration , I was thinking  maybe  pg_hba.conf file  ?
Thank you
Isabella

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Isabella A. Ghiurea

Isabella.Ghiurea@nrc-cnrc.gc.ca
Canadian Astronomy Data Centre |http://www.nrc-cnrc.gc.ca/eng/services/hia/data-centre.html
National Research Council of Canada, Herzberg Institute of Astrophysics
5071 West Saanich Road, Victoria BC V9E 2E7, Canada
Phone: 250 363-3446 fax: 250 363-0045